90 "^he Philippine Journal of Science i»i» 



Magnetite — FCjO^. 



Magnetite is widespread in small particles throughout the 

 igneous rocks in the Philippines. It is also associated with the 

 hematites of the Eastern Cordillera, Luzon. Fine octahedral 

 crystals (No. 319) from San Miguel de Mayumo, Bulacan, Luzon, 

 are in the collection of the Ateneo de Manila. 



Magnetized iron ore — Lode stone. Apparently iron oxides. 



This ore is found near Paracale, Camarines, and is also 

 reported near Casiguran, Tayabas. No deposits are worked. 



Malachite— (Cu. 0H)X03. 



No large crystalline samples of malachite are on record. This 

 mineral is present in most of the copper deposits as a green 

 coating. 



Manganite— MnO (OH) . 



Manganite occurs possibly with wad or pyrolusite in mineral 

 veins, and often contains high values in gold. It is soft, and ia 

 derived from other manganese ores. It is found in several veins 

 in Baguio and Suyoc, Mountain Province, and in Aroroy, Mas- 

 bate. It has no economic value in the manner of its occurrence 

 in the Philippines. 



Marcasite — FeSo . 



Marcasite is similar to pyrite, but is whiter. It is apparently 

 infrequent. Marcasite has been reported from Mancayan, 

 Luzon. 



Margarite — HXaAl.SijOjj. 



Margarite is a white mica occurring in certain schistose rocks 

 of Ilocos Norte. No use is made of it, nor is there any production. 



Mercury — Hg (metallic). 



Mercury is reported to occur in small crevices and pockets on 

 Mount Isarog, Albay, Luzon. A small phial of it is in the mu- 

 seum of the Ateneo de Manila. 



Minium— PbO. 



A large amorphous pink specimen of this mineral is in the 

 museum of Santo Tomas University, marked "Filipinas;" no 

 other dat-a are given. 



Molybdenite — MoS„. 



Molybdenite is found in characteristic form in steel-blue flakes 

 and leaves in quartz veins, Loboo Mountains, Batangas Province, 

 Luzon. Only a small amount is found. 



